Aberrant DNA methylation has been reported as an important phenotype in acute myeloid leukemia. However the clinical significance of methylation changes has not been clear yet. In this study methylation Specific Melting Curve Analysis (MS-MCA) and real time PCR was used to assess the CDKN2B promoter hyper-methylation and gene expression in 59 Iranian acute myeloid leukemia (AML) patients. The incidence of aberrant hyper methylation of CDKN2B gene and cytogenetic abnormalities were 37.3% (22 of 59 patients) and 35.6% (21 of 59) respectively in our patients. We observed that CDKN2B expression level was lower than normal mesenchymal stem cells. Our data revealed significant correlation between methylated CDKN2B promoter region and mRNA gene expression (P= 0.007). Also, our data indicated that AML patients with aberrant methylation of CDKN2B gene had a lower survival rates (P=0.043). In addition they had a higher proportion of leukemic blast cells (P=0.022) and higher white blood cell count in peripheral blood (P=0.0123). Aberrant methylation of CDKN2B was observed to higher in M2 subtype and lower in M3 and M4 subtypes. Although we observed a significant correlation between Methylation and survival, there was no significant correlation between CDKN2B methylation and treatment outcome of AML patients (P= 0.187). Furthermore, our data didn’t illustrated a significant correlation between CDKN2B expression and survival (P=0.93). In conclusion our study showed that the aberrant methylation is one of molecular mechanisms involved in CDKN2B gene expression, moreover we can consider the CDKN2B methylation, as a prognostic marker in predict AML patients’ survival.